Temperatures can get very low in Las Vegas during the winter and the exposed pipes and outside faucets can freeze. It is important to cover them. Once they freeze, they will crack, leak and will have to be replaced.
Insulated covers for outdoor faucets, hose bibbs or hose spigots can be bought at Home Depot or Lowes. They are easy to install and prevent the faucets from freezing.
Pipes should be buried in the ground. However, if you have any exposed irrigation pipes, you should make sure they are covered and protected against freezing. Once they freeze, the water inside expands and makes them crack. When thawed, they will start leaking and will have to be replaced. Insulation options for pipes are available to buy. However, if you cannot get them, cover them with blankets and that will add a layer of protection to prevent the pipes and lines from freezing.
It is more expensive than what it costs to cover and prevent them from freezing.